1. Field of the Invention
The present invention relates to a data communication apparatus having a function of monitoring information or a communication line.
2. Related Background Art
As an example of apparatus of this type, there is known a facsimile apparatus having a function of monitoring information on a line by outputting from a loudspeaker audible sounds corresponding to signals on the line.
Every time a signal from a sending party is received by the facsimile apparatus, the monitor (loudspeaker) is turned one and kept in this condition until a significant signal (e.g., preamble signal, tonal signal or phase signal (PHS)) is detected.
The object of monitoring is to notify the operator at the facsimile apparatus of the fact that an operator at a sending party is calling via a telephone set.
In sending and receiving data over a dedicated facsimile communication line, an operator is not requested to communicate by speech in any case. However, the apparatus monitors the line also in this case.
As a result, procedure signals for facsimile communication and image signals are converted into audible sounds and outputted from a loudspeaker, resulting in a problem of a very noisy environment.